The Tappan Zee Bridge is built out of concrete, timber piles, steel H pile, steel piping and trusses. Located about 25 miles north of midtown Manhattan, the total length of the bridge is nearly 16,013 feet long.
The bridge is supported by eight underwater concrete caissons, which support about 70 percent of the bridge’s dead weight. Each caisson is supported by steel piles driven to rock, and incorporates a buoyant design that stores pressurized air inside compartments. The bridge utilizes a steel tied-arch span along with a cantilever design. On each side of the main and side cantilever span are 19 deck truss spans.
The Tappan Zee Bridge is part of the New York State Thruway system and opened in 1955. Located about 25 miles north of midtown Manhattan, it connects South Nyack in Rockland County with Tarrytown in Westchester County in the Lower Hudson Valley.